Preliminary Estimation for Contribution of Nuclear Power to Reduce Emission of Air Pollutants from Electricity Sector in Japan

Abstract

Figure 1:
The first figure shows the historical trend of electricity mixes
in Japan in the last 30 years. The second figure shows the total
CO2 emission from the electricity sector in Japan
and the hypothetical CO2 emission assuming nuclear
energy had not been introduced
(the blue region is the actual emission).

Nuclear power plants emit almost no air pollutants
such as SOx, NOx, particulates
and greenhouse gases (GHG) during plant operation,
and their energy balance, i.e. the ratio of energy
output versus energy input, is very low compared to
fossil fuel energy. These facts imply that the
introduction of nuclear power contributes to reducing
the emission of these air pollutants. Of course, it is
not possible to evaluate exactly what would have
happened if nuclear power had not been introduced,
because, elimination of nuclear energy from energy
options would have changed the entire structure of
economic activities relating to energy production and
consumption. For the same reasons, evaluation of
contributions of nuclear power to mitigating air
pollution in the future is also difficult. Nevertheless, it
is possible to provide useful estimates of
how the introduction of nuclear
power mitigated the environmental impact in the past
or how it can mitigate the air pollution in the
future. This paper first describes the energy mixes of the
past in Japan and the history of the
improvement of emission factors of air pollutants.
This paper also provides
preliminary results of calculations of the
emission of air pollutants from the electricity sector in
Japan in the case nuclear power had not been
introduced but instead the electricity had been produced
by thermal power. We also provide some
consideration of the role of nuclear energy in the future.